GL_SGIS_sharpen_texture http://www.opengl.org/registry/specs/SGIS/sharpen_texture.txt GL_SGIS_sharpen_texture void glGetSharpenTexFuncSGIS (GLenum target, GLfloat* points) void glSharpenTexFuncSGIS (GLenum target, GLsizei n, const GLfloat* points)